74 ideas
16227 | Philosophers are good at denying the obvious [Hawley] |
15413 | With four tense operators, all complex tenses reduce to fourteen basic cases [Burgess] |
15415 | The temporal Barcan formulas fix what exists, which seems absurd [Burgess] |
15430 | Is classical logic a part of intuitionist logic, or vice versa? [Burgess] |
15431 | It is still unsettled whether standard intuitionist logic is complete [Burgess] |
15429 | Relevance logic's → is perhaps expressible by 'if A, then B, for that reason' [Burgess] |
15404 | Technical people see logic as any formal system that can be studied, not a study of argument validity [Burgess] |
15405 | Classical logic neglects the non-mathematical, such as temporality or modality [Burgess] |
15427 | The Cut Rule expresses the classical idea that entailment is transitive [Burgess] |
15421 | Classical logic neglects counterfactuals, temporality and modality, because maths doesn't use them [Burgess] |
15403 | Philosophical logic is a branch of logic, and is now centred in computer science [Burgess] |
15407 | Formalising arguments favours lots of connectives; proving things favours having very few [Burgess] |
15424 | Asserting a disjunction from one disjunct seems odd, but can be sensible, and needed in maths [Burgess] |
15409 | All occurrences of variables in atomic formulas are free [Burgess] |
16216 | Part of the sense of a proper name is a criterion of the thing's identity [Hawley] |
15414 | The denotation of a definite description is flexible, rather than rigid [Burgess] |
15406 | 'Induction' and 'recursion' on complexity prove by connecting a formula to its atomic components [Burgess] |
15425 | The sequent calculus makes it possible to have proof without transitivity of entailment [Burgess] |
15426 | We can build one expanding sequence, instead of a chain of deductions [Burgess] |
15408 | 'Tautologies' are valid formulas of classical sentential logic - or substitution instances in other logics [Burgess] |
15418 | Validity (for truth) and demonstrability (for proof) have correlates in satisfiability and consistency [Burgess] |
15412 | Models leave out meaning, and just focus on truth values [Burgess] |
15411 | We only need to study mathematical models, since all other models are isomorphic to these [Burgess] |
15416 | We aim to get the technical notion of truth in all models matching intuitive truth in all instances [Burgess] |
15428 | The Liar seems like a truth-value 'gap', but dialethists see it as a 'glut' [Burgess] |
10185 | Set theory is the standard background for modern mathematics [Burgess] |
10184 | Structuralists take the name 'R' of the reals to be a variable ranging over structures, not a structure [Burgess] |
10189 | There is no one relation for the real number 2, as relations differ in different models [Burgess] |
10186 | If set theory is used to define 'structure', we can't define set theory structurally [Burgess] |
10187 | Abstract algebra concerns relations between models, not common features of all the models [Burgess] |
10188 | How can mathematical relations be either internal, or external, or intrinsic? [Burgess] |
16211 | A homogeneous rotating disc should be undetectable according to Humean supervenience [Hawley] |
16219 | Non-linguistic things cannot be indeterminate, because they don't have truth-values at all [Hawley] |
16223 | Maybe for the world to be vague, it must be vague in its foundations? [Hawley] |
16226 | Epistemic vagueness seems right in the case of persons [Hawley] |
16208 | Supervaluation refers to one vaguely specified thing, through satisfaction by everything in some range [Hawley] |
16221 | Supervaluationism takes what the truth-value would have been if indecision was resolved [Hawley] |
16230 | Maybe the only properties are basic ones like charge, mass and spin [Hawley] |
16232 | An object is 'natural' if its stages are linked by certain non-supervenient relations [Hawley] |
16200 | Are sortals spatially maximal - so no cat part is allowed to be a cat? [Hawley] |
16237 | The modal features of statue and lump are disputed; when does it stop being that statue? [Hawley] |
16238 | Perdurantists can adopt counterpart theory, to explain modal differences of identical part-sums [Hawley] |
16220 | Vagueness is either in our knowledge, in our talk, or in reality [Hawley] |
16222 | Indeterminacy in objects and in properties are not distinct cases [Hawley] |
16228 | The constitution theory is endurantism plus more than one object in a place [Hawley] |
16229 | Constitution theory needs sortal properties like 'being a sweater' to distinguish it from its thread [Hawley] |
14492 | If the constitution view says thread and sweater are two things, why do we talk of one thing? [Hawley] |
16193 | 'Adverbialism' explains change by saying an object has-at-some-time a given property [Hawley] |
16195 | Presentism solves the change problem: the green banana ceases, so can't 'relate' to the yellow one [Hawley] |
16202 | The problem of change arises if there must be 'identity' of a thing over time [Hawley] |
16192 | Endurance theory can relate properties to times, or timed instantiations to properties [Hawley] |
16196 | Endurance is a sophisticated theory, covering properties, instantiation and time [Hawley] |
16197 | How does perdurance theory explain our concern for our own future selves? [Hawley] |
16191 | Perdurance needs an atemporal perspective, to say that the object 'has' different temporal parts [Hawley] |
16199 | If an object is the sum of all of its temporal parts, its mass is staggeringly large! [Hawley] |
16201 | Perdurance says things are sums of stages; Stage Theory says each stage is the thing [Hawley] |
16240 | If a life is essentially the sum of its temporal parts, it couldn't be shorter or longer than it was? [Hawley] |
16203 | Stage Theory seems to miss out the link between stages of the same object [Hawley] |
16204 | Stage Theory says every stage is a distinct object, which gives too many objects [Hawley] |
16212 | An isolated stage can't be a banana (which involves suitable relations to other stages) [Hawley] |
16213 | Stages of one thing are related by extrinsic counterfactual and causal relations [Hawley] |
16205 | The stages of Stage Theory seem too thin to populate the world, or to be referred to [Hawley] |
16206 | Stages must be as fine-grained in length as change itself, so any change is a new stage [Hawley] |
16225 | If two things might be identical, there can't be something true of one and false of the other [Hawley] |
15420 | De re modality seems to apply to objects a concept intended for sentences [Burgess] |
15419 | General consensus is S5 for logical modality of validity, and S4 for proof [Burgess] |
15417 | Logical necessity has two sides - validity and demonstrability - which coincide in classical logic [Burgess] |
15422 | Three conditionals theories: Materialism (material conditional), Idealism (true=assertable), Nihilism (no truth) [Burgess] |
15423 | It is doubtful whether the negation of a conditional has any clear meaning [Burgess] |
16239 | To decide whether something is a counterpart, we need to specify a relevant sortal concept [Hawley] |
16218 | On any theory of self, it is hard to explain why we should care about our future selves [Hawley] |
16215 | Causation is nothing more than the counterfactuals it grounds? [Hawley] |
16207 | Time could be discrete (like integers) or dense (rationals) or continuous (reals) [Hawley] |
7902 | The Buddha made flowers float in the air, to impress people, and make them listen [Mahavastu] |